1. Field of the Invention
This invention pertains to stitchbonded articles and to methods of producing such articles. Particularly, stitchbonded articles having absorbent and/or scrubbing abilities are described.
2. Related Art
Parella, J. C., "Nonwoven Technology and Wipers", paper presented at INDA-TEC I989, presents a perceptive account of the nonwoven industry. Specifically, Parella describes and compares the four primary techniques that commercial manufacturers have focused on for producing absorbent wipes. In order of commercialization they are:
dry staple (carded, air laid, saturation or spray bonded webs made from textile fibers);
air-lay (fabric made by air laying and bonding cellulosic or synthetic pulp fibers);
melt blown (webs formed by in-line melt spinning of very fine fibers); and
spunlace (fabrics produced by hydraulic entangling of fibers).
Parella compares these primarily using the "alphabet" of consumer driven requirements for wipes: "A" for absorbency; "B" for bulk density; "C" for consistency; "D" for durability; and "P" for price.
Dry staple nonwoven wipes were acceptable in terms of A and D, but P was a premium over 100% cellulosic paper wipes. Absorbent wipes made using the air-lay process generally met consumer needs for A, B, C, and P but fell short on improving D over already available dry staple nonwoven wipes. Despite this, product acceptance was almost immediate in industrial and consumer sectors. Fabrics made from melt blown fibers exhibited outstanding oil absorbency, and aqueous absorbency was acceptable. Adsorption or entrapment is the method of absorbency employed rather than absorption into the fiber or cellulose as in the use of the dry staple or air laying techniques. B, C, D, and P were adequate but not dramatically different from prior wipes. Spunlaced fabrics were said to be "the most complete nonwoven wiper seen to date" in terms of A, B, C, and D, and P was "within the range of acceptance given the performance characteristics. "
Stitchbonding, as a method of bonding two fabrics together to form a durable, absorbent wipe, has apparently not received the amount of attention of the wipes industry as have the above mentioned techniques.
There are numerous stitchbonded materials which include thermoplastic material in some manner incorporated into the material. For example, U.S. Pat. No. 5,104,703 discloses a single layer nonwoven fabric that is a single layer batt formed of crosslapped fiber, having a structure compacted by needle tacking, and being thermally bonded by thermally setting a low melting thermoplastic material intermixed throughout the batt. The batt is stitched through. U.S. Pat. No. 4,740,407 describes a pile-like substrate comprising a textile carrier body consisting of fibers and having a rough surface on at least one side, being at least partially impregnated with a polymeric synthetic plastics-material having a foam-like condition. The substrate is ground on at least one impregnated surface such that the fibers of the carrier body protrude at least partially out of the substrate.